Refrigerating apparatus



F. w. ANDREWS 1,726,791

Sept. 3, 1929.

REFRIGERATING APPARATUS Filed April 28; 1927 3 Sheets-Sheet l 26 //7' J F ,u

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Sept. 3, 1929. F. w. ANDREWS 1,726,791

REFRIGERATING APPARATUS Filed April 28, 1927 s Sheets-Sheet 2 60 /1 0 5y 3/ W m4 6 7 "'l! Z I Y, r/ 5/ Z 7/ 9/ i Y LL '40 M a2 .4. (j gwue'nto'o 1M W Q Sept. 3, 1929. w ANDREWS 1,726,791

REFRIGERATING APPARATUS Filed April 28, 1927 35heets-Sheet 5 rhea ll 5/ %%\S;WLUL WVYA Patented Sept. 3, 1929.

UNITED STATES PATENT OFFICE.

FRANK W. ANDREWS, OF DAYTON, OHIO, ASSIGNOB, BY MESNE ASSIGNMENTS, TO ,FRIGIDAIRE CORPORATION, A CORPORATION OF DELAWARE.

REFRIGERATING APPARATUS.

Application filed April 28, 1927. Serial No. 187,352.

This invention relates to refrigerating apparatus of the type comprising a compressor, a water-cooled condenser and evaporator, particularly to arrangements for controlling the starting and stopping of the apparatus and the regulation 0 of cooling water.

It is among the objects of the invention to provide a simple and reliable device for turning on a supply of cooling water when the apparatus is running and turnlng off the cooling water when the apparatus is stopped.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of embodiment of the present invention is clearly shown.

In the drawings:

Fig. 1 is a diagrammatic illustration of a complete refrigerating system to whlch my invention is applied.

Fig. 2 is a vertical section thru the automatic switch and water valve in position to 25 permit operation of the system.

Fig. 3 is a similar section thru the same devices showing their positions when the system is not operating.

Fig. 4 is a section on the line 4-4 of Fig. 2.

Fig. 5 is a view part1 in plan and partly in section of adetail o the switch.

Fig. 6 is a vertical section thru the switch 'on the line 6-6 of Fig. 2.

Fig. 7 is a horizontal section on the line 7-7 of Fig. 2.

Fig. 8 is a side elevation of the water valve.

Referring particularly to Fig. 1, represents a compressor, driven by an electric motor 21, and connected to a condenser 22 1ncluding a cooling coil 23, and to an evaporator 24. The compressor withdraws gaseous refrigerant from the evaporator thru the conduit 25, and compresses the refrigerant and forces it into the condenser thru the conduit 26. Liquid refrigerant flows from the condenser to the evaporator thru conduit '27 and evaporates therein producing refrigeration in the well known manner. The motor is controlled to drive the compressor in response to refrigerating demand by means of an automatic switch 30. The switch is actuated by a pressure responsive cell 31 connected to the conduit 25 by means of a connection 32, and is therefore actuated in rethe supply sponse to the pressure existing in the evaporator, as is known in the art.

Cooling water or other liquid cooling medium is supplied to the condenser coil 23 thru a conduit 33 under the control of a valve 34. The automatic switch 30 includes an arm 35 which is elevated when the switch is closed and depressed when the switch is open and which is connected by a link 36 to an arm 37 to 0 en and close the water valve.

T e particular structure of valve forms no part of the present invention, but a structure suitable for the purpose is shown for the sake of example in Figs. 2, 3 and 8. The valve includes a casing 40 having the usual screwthreaded openings 41 for connection with pipes and a chamber 42 containing a rotatable member 43 which has a passageway 44 and a stem 45 by which it may be rotated. Member 44 is held in place by a packing gland 48 in a boss 46 closed by a suitable cap 47. The valve is opened and closed by turning the rotatable member 43 so that its passageway 44 is in alignment with the openings 41 and transverse to the openings, respectively. On the end of the stem 45 is keyed the arm 37.

Figs. 2 to 7 inclusive illustrate a switch which is adapted to the system under consideration. However the particular structure of this switch forms no part of the present invention, any switch which can be operated in response to the pressure of evaporator 24 and which can be mechanically connected to the water valvebeing suitable for the purposes of the invention. The switch has a ase 50, casing 51 and top plate 52 secured together in any suitable manner. The base is made of insulation and carries a pair of contacts in the form of cups 53 containing mercury 54 which is connected to the motor and power lines 55 by suitable binding posts 56. Contacts 57 are mounted on a bar of insulation 58 and electrically connected by any suitable means, such as a wire 59 and are 100 adapted to be lowered into contact with the mercury to connect the lines 55 or to be raised out of contact with the mercury to break the power circuit.

The mechanism which I have employed 105 for raising and lowering the contacts 57 in response to the refrigerating demand includes a pressure res onsive cell 31 which may be secured over t e opening of the to plate 52 in any suitable manner and inclu es 8. fiex- 110 ible diaphragm 61. A bar 62 is connected at one end to the center of the diaphragm 61' and at its other end carries the switch bar 58. The bar 62 is adapted to slide vertically in a bearing sleeve 63, suitably supported by a spider 64 attached to the cover plate 52. The pressure cell 31 has a threaded opening 65 for connection with the conduit 32 leading to the evaporator. Thus the position of the diaphragm 61 directly depends upon the pressure existing in the evaporator. \Vhen the pressure is high, that is, when refrigeration is required, the diaphragm is bulged outwardly as in Fig. 2 and the switch contacts are closed to actuate the motor. When the refrigeration demand has been supplied the pressure in the evaporator is lowered and the diaphragm takes the position shown in Fig. 3, the contacts being elevated to open the circuit and stop the motor. The valve-actuating arm 35 is pivoted at 7 0 to the spider 64. and one end of the arm is connected to the bar 62 by a pin and slot connection 71. Thus the other end of the bar is elevated to open the water valve when the switch contacts are closed as shown in Fig. 2 and is depressed to close the water valve when the switch is open, as shown in Fig. 3.

In order to make the operation of the switch and water valve more positive I may provide a snap-acting mechanism as follows. Referring particularly to Figs. 5 and 6, rigidly attached to the bar 62 and below the switch bar 58 is a member 80 having a transverse slot 81 which receives a crank 82 mounted on one end of a shaft 33 which is rotatable in bearings 84: and 85 and which. carries at its other end an arm 86 having a weight 87. With the apparatus in the position shown in Fig. 2 a decrease in pressure in the cell 60 rot-ates the weighted arm 86 counterclockwise until it is in a vertical position. A very slight decrease in pressure beyond this point throws the weight beyond its dead center position and it drops to the position shown in Fig. 3, positively and rapidly raising the contacts from mercury cups. As the weight approaches its center position from the position shown in Fig. 2, its moment on the shaft 83 and consequently its resistance to the force acting on the diaphragm substantially decreases. Therefore, when the pressure begins to decrease enough to move the weight, the switch can open very rapidly. Conversely with the apparatus in the position shown in Fig. 3, an increase 'in the pressure rapidly rotates the weight to the center position from Which it drops to the position shown in Fig. 2 to close the switch.

In order to adjust the pressure values at which the switch opens and closes I provide a bell crank lever 90 which is mounted on the same pivot which carries the water valve arm 35, one end of which is connected to the bar 62 by a pin and slot connection 91. The

other end of the bell crank lever is pivoted to a spring guide 93 which carries a spring 94 between a collar 95 and an abutment 96 which latter is pivoted at 97 to the spider 64 and may be adjusted by means of screw 98. The bell crank lever 90 carries on its pivot 93 a roller 100 shown best in Figs. 6 and 7. A fork 101 is pivoted to the bearing sleeve 63 at 102 and near its other end carries a pointed cam 103. The cam is urged against the roller by a spring 105 bearing against an adjusting screw 106.

The spring 94 constantly urges the bell crank lever 90 counterclockwise which tends to lower the bar 62 and consequently assists the diaphragm 61 to close the switch. This therefore assists the diaphragm in lifting the weight 87 from the position shown in Fig. 3 to its center position. Therefore by adjusting the tension of the spring 94% by means of screw 98 the pressure value at which the switch will close can be adjusted to suit operating conditions. As the bar 62 moves from one extreme position to the other the bell crank lever 90 is rotated and the roller 100 elevates the cam 103. The maximum elevation of the cam occurs when the point of the cam is in contact with the roller, which is when the weight 87 is in central position. Therefore a slight movement either side of the center causes the roller to move past the point of the cam. When this occurs the spring 105 urges the cam downwardly and the sloping face of the cam hearing on the roller urges the hell crank arm 90 ahead. The roller and cam therefore constitute a snapacting mechanism acting in conjunction with the weight 87 and furnishing a further means for adjusting the pressure value at which the switch will operate.

From the foregoing description it will be appreciated that as the pressure within the evaporator increases the switch is closed to start the motor and due to the links 35, 36 and 37 the water valve is positively opened when the switch is closed. Consequently a supply of cooling water to the condenser is assured whenever the motor starts. Converse- 1y whenever the switch is opened to stop the motor the other position closes the water valve to stop the supply of cooling water and thus prevents waste which would be caused by cooling water flowing when the apparatus is not running. I

While the form of embodiment of the pres ent invention as herein disclosed, constitutes a preferred form, it is to he understood that other forms might be adopted, all coming,

within the scope of the claims which follow.

What is claimed is as follows:

1. Refrigerating apparatus comprising an evaporator, a condenser, a compressor adapt ed to withdraw gaseous refrigerant from the evaporator and force it into the condenser, means for cooling the condenser including a conduit for cooling medium, means for driv ing the com ressor, means responsive to the pressure in t e evaporator for controlling the driving means, means for controlling the flow of cooling medium thru the conduit, said last mentioned means having a positive mechanical connection with the controlling means.

2. Refrigeratin apparatus comprising an evaporator, a con enser, a compressor adapted to withdraw gaseous refrigerant from the evaporator and force it into the condenser, means for cooling the condenser including a conduit for cooling medium, a valve in said conduit, means for driving the compressor, a switch for controlling the driving means, means responsive to pressure in the evaporator for opening and closing the switch and a positive mechanical connection between the switch and valve for opening the valve when the switch is closed and closing the valve when the switch is open.

In testimony whereof I hereto afiix my signature.

FRANK W. ANDREWS. 

